Grand Slam-winning fly-half Craig Chalmers believes a Scotland victory over England on Saturday would eclipse the southern hemisphere scalps of Australia and South Africa.

Scotland have not tasted victory at Twickenham since 1983 and Chalmers has no doubt that a rare success at England's HQ would be the highlight of Andy Robinson's 18-month tenure as head coach that has included hard-fought victories over the Wallabies and the Springboks.

Scotland entered the tournament on a run of five wins in six Tests - the only defeat coming to New Zealand - but they have lost each of their three games so far - to France, Wales and Ireland - and on Sunday meet an England side with a 100% record and targeting a first tournament title since 2003.

But Chalmers, part of the team that beat England at Murrayfield in 1990 to secure the Grand Slam, would not be surprised if Scotland seize on complacency to return home from west London with a win for the first time in 28 years.

"To beat southern hemisphere sides is outstanding, but winning at Twickenham would be bigger than those results and I think it would mean an awful lot more to the people of Scotland as well," the 42-year-old told PA Sport. "We've not beaten them there since 1983; I was involved in a 12-all draw in 1989. It's a tough place to go, it's quite an intimidating venue and at the moment England are full of confidence.

"But that's probably when they're at their most vulnerable - when they're over-confident and people are telling them they're going to beat Scotland by 20, 30 points. It's not going to happen that way. It will be a lot tougher game than some people are predicting."

Chalmers believes Scotland will not be satisfied with their Championship performance even if they secure victory over England on Sunday and then Italy on March 19. Speaking at the launch of the Melrose Sevens, he added, "Victory this weekend against England wouldn't brush under the carpet a lot of problems.

"Andy and his coaching team can see them, but they've got to stand by what they've got. I thought three wins would be a good return for us this year. It would be disappointing to come out of the Championship with two wins or even one."

Glasgow Warriors centre Graeme Morrison was a key component of Robinson's team prior to the tournament, but a knee injury is set to keep him out for the whole campaign.
Further injuries in the backs have necessitated change and Robinson is still seeking to find the right mix, but Chalmers does not anticipate too many changes when the Scotland team is announced on Wednesday.

"There needs to be continuity, it's the only way teams can move forward," added the Melrose coach. "You can't keep shuffling it around and I don't think Andy will make too many changes to the team."

One area in which Chalmers will take a particular interest is who occupies the No.10 jersey as Scotland's playmaker. Ruaridh Jackson won his fourth cap as he started at fly-half against Ireland, suggesting a more expansive game plan, but Dan Parks, with his tactical kicking game, has been key in Scotland's recent success and performed well when he came on as a replacement.

"It's a real dilemma at the moment. I can see points for either of them," he said. "I don't know what the tactics were against Ireland but there was an awful lot of kicking. I thought Ruaridh was brought into the team to get the ball moving, but he ended up playing deep and kicking the ball in the air, which I don't think is his game - it's more Dan's game.

"If they kick a ball into the corners, behind England, then Dan's your man - he's very, very good at that. But if it's to play flatter, to try and play a bit more rugby, then you start with Ruaridh."

Chalmers would like to see Scotland attacking England. "They've got to try and play, they've got to mix it up," he added. "England can be vulnerable like anyone else."